The proposed work seeks to determine the biochemical mechanism for the increased purine and uric acid production in gout. The approach being taken includes correlating key purine enzyme activities, the net flux of radioactively labelled purines through the purine pathways and total uric acid production under conditions of known and variable uric acid production. Uric acid production is being altered by dietary manipulation (protein level, absorptive and post absorptive state). Enzyme, purine flux and total purine production measurements are also being made on cultured skin fibroblasts from humans known to be overproducers of uric acid. BIBLIOGRAPHIC REFERENCES: Clifford, A.J., Steine, L. & Castles, J.J. (1977) Activities of purine pathway enzymes in gouty human fibroblasts aged in vitro. Clin. Chim. Acta 74, 255-260. Vasconcellos, J.A., Miller, M.W., Weir, W.C. & Clifford, A.J. (1977) Growth and metabolism of rats fed heat dried and freeze dried yeasts. Nutrition Reports Internatl., February Issue.